In the past, most medical devices operated as stand-alone devices that would either record physiological information from the patient or be operated to supply some therapy or treatment to the patient. FIG. 1 shows a medical system 100 that is limited to monitoring a patient's vital signs and recording physiological information from the patient. The system 100 uses an electrocardiogram acquisition module 102 to acquire electrocardiogram data of a patient 101 and forward such data to a PalmPilot™ 104. The PalmPilot 104 can be controlled to start or stop the recording of the electrocardiogram data. Other information, such as name and age of a patient, can also be recorded along with the electrocardiogram data associated with the patient 101. While recording, the PalmPilot 104 displays the electrocardiogram data as waveforms in real time. The user can change the gain or the zoom to see more details of the waveforms. For proper communications between the electrocardiogram acquisition module 102 and the PalmPilot 104, the PalmPilot 104 must be compatible with the software version installed on the electrocardiogram acquisition module 102.
Other medical devices have advanced to the point where they not only can monitor a patient but they can also apply a therapy to the patient to treat various ailments. These medical devices can be tailored to a particular patient by modifying the parameters relating to a particular medical protocol used to treat the patient. For example, if a patient is in defibrillation, the medical protocol may require a sequence of shocks to be applied to the patient. The energy level of each shock can be modified. Or, the sequencing of a medical protocol can be modified so that the device automatically executes each step in the medical protocol without further human intervention.
To vary or program the parameters of the medical device, the parameters can be retrieved from the medical device. To do that, a terminal is needed to communicate with the medical device because most medical devices do not have a user interface. However, the communication between the terminal and the medical device may be impossible unless the terminal is compatible with the version of software installed on the medical device. The problem is that as different generations of devices and terminals are distributed into the marketplace, it can be exceedingly difficult to obtain a compatible terminal to communicate with the device having a particular version of software. The medical system 100 illustrates such a problem in that if the electrocardiogram acquisition module 102 were to be distributed with a version of software not known to the PalmPilot 104, the PalmPilot 104 may not be able to obtain any physiological information or be able to control the electrocardiogram acquisition module 102.
Furthermore, the current trend among designers of medical equipment is to integrate such equipment into an overall system whereby the equipment can be programmed by an operator in a manner that is specific to a particular patient's needs as well as to have the equipment operate in conjunction with other pieces of the system. In order to facilitate such a system integration, it is necessary to provide a common protocol that can be used to either read data from or write data to a particular medical device. Because many devices have different versions of operating software, it is desirable that communications to these devices operate in a predictable manner regardless of the version of operating software on each device.
Another prior art solution is shown in FIG. 2 where a medical system 200 includes a treatment device 202 that is engineered with all the rules, parameters, and user interface features necessary for the treatment device 202 to communicate with a number of terminals 204-208. In other words, the treatment device 202 contains all of the intelligence necessary to treat a patient as well as the ability to present a user interface to configure the treatment device 202. When one of the terminals 204-208 has successfully connected to the treatment device 202, the treatment device 202 presents a user interface, which is displayed on one of the terminals 204-208, so that a user may control the treatment device 202 or read data from it. To ensure compatibility with multiple generations of terminals 204-208, however, the medical device 202 must be constantly updated and marketed at a price that is prohibitively expensive for many customers.